The present invention relates to two or three way ball valves and more particularly to motorized ball valves used in heating, ventilating and air conditioning applications.
As an example, a two way Ball valve such as the one shown in prior art FIG. 1 are known in the art. Typically, the ball valve 100 included a valve body 105, a sphere 110, a shaft 115, a linkage arm 120, a sphere shaft 125, a Teflon sleeve 132, a bore 130, O rings 140, retainer ring 145, thrust washer 150, plate assembly 155, fasteners 160, stake 165 and stake 170. Shaft 115. in operation, was mated to a motor which when activated would rotate the shaft in order to reposition the sphere 110. Shaft 115 passed through bearing 175 into the interior of the valve housing 105. The valve housing 105 when mated with plate assembly 155 defined in an enclosed space through which a fluid such as water could pass.
Shaft 115 was typically made of stainless steel. The shaft was then connected to linkage arm 120. Linkage arm 120 typically was made of brass and was formed having two holes therein 180, 190. The shaft was liked to the linkage arm by having one portion of the shaft pass through hole 190. A staking operation to produce stake 170 was then performed to join the shaft and the linkage arm.
Similarly, sphere 110 is joined to linkage arm 120 through use of the sphere shaft 125. A staking operation was performed on sphere shaft 125 to form a head 127 which prevented the shaft from passing entirely through hole 180. The head 127 could be pre-formed using other means. Sphere 110 included bore 130 through which sphere shaft 125 could pass. Sphere 110 was typically made of an elastomeric material such as rubber. The ball was maintained on the shaft through use of washer 135 and stake 165. In some embodiments, a sleeve was placed inside bore 132 as a bearing surface to provide for rotation of sphere 110 during some valve operations.
O rings 140 prevented fluid from escaping through bearing 175. Retainer ring 145 held shaft 115 in place and prevented axial movement of the shaft into the bearing 175. Similarly, thrust washer 150 prevented axial movement of the shaft 115. Fasteners 160 were used to attach the plate assembly 155 to the valve body 105. Serration 180 provides a tight fit for assembly and prevents axial movement of shaft 125. Referring now to prior art FIG. 3, there shown is a top sectional view of the valve 100. The valve 100 includes fluid inlet 192 and fluid outlet 194. In operation, sphere 110 is moved toward or away from fluid inlet 192 on an arc through rotation of shaft 115. The closer that sphere 110 is to the mid point between fluid inlet 192 and fluid outlet 194, the greater the flow of fluid through the valve. As sphere 110 moves towards either the fluid inlet or the fluid outlet, flow through the valve is restricted. In the prior art, to shut off flow through the valve, sphere 110 was placed in contact with outside edge 196 and inside edge 198 to prevent fluid flow through fluid inlet 192. Again in the prior art, sphere 110 first made contact with outside edge 196 and then with inside edge 198. This caused rotation of sphere 110 about shaft 115 in the direction of arrow 199.
However, several problems existed with the prior art. First, many manufacturing operations are required to create multiple parts and the assembly of the sphere-crankshaft assembly. Shaft 115 must be machined. Linkage arm 120 must be stamped with two holes in it. Shaft 115, linkage arm 120 and sphere shaft 125 must be staked together.
In addition, four basic parts were required to make the crankshaft assembly. Further, since the shaft 115 and sphere shaft 125 were usually made of stainless steel, and the linkage arm 120 was made of brass, galvanic corrosion could occur at the joints of the dissimilar materials.
Lastly, because of the various machining requirements for the four separate parts, it was more difficult to place the tight fit sleeve 132 and sphere 110 correctly on the shaft. This was due to the accumulation of errors due to machining tolerances soldering and staking of the shaft components.